1. Field of the Invention
The present invention pertains to the art of refrigerators and, more particularly, to a refrigerator appliance incorporating a rapid cooling system.
2. Discussion of the Prior Art
A typical refrigeration system includes a compressor, an evaporator, a condenser and an expansion device, used in combination with either a blower or natural convection, to develop and direct a flow of cooling air into a compartment to be refrigerated. A common household refrigerator is typically configured to establish and maintain a selected temperature environment within a compartment thereof with a flow of cooling air being directed to a freezer compartment and a percentage of that air being diverted into a fresh food compartment such that the freezer compartment is maintained at a lower temperature. Deep freezers, which also include corresponding refrigeration system components, are also known in the art. In some known systems, provisions are made for rapidly cooling food items placed in a compartment of the unit. These deep freezers can be utilized for various purposes, particularly in connection with rapidly freezing food items which can deteriorate or spoil rather quickly if exposed to higher temperatures. Often times, provisions are made to direct a refrigerating agent into the compartment of the freezer to perform the rapid cooling function.
In general, deep freezer arrangements are not found in common households, mainly due to the fact that known deep freezers have a single dedicated function and there is a general lack of need to rapidly freeze a large amount of food products in this environment. However, it would be beneficial to provide a refrigeration appliance which could be used in various modes of operation to efficiently and effectively enable a consumer to take advantage of the ability to rapidly freeze food items, while also not requiring the appliance to be dedicated to performing such a task. In addition, there is considered to be a need in the art for a refrigeration appliance that could be used to quickly freeze food items, but which can also be used to simply chill or maintain food at a desired temperature, preferably in a domestic household environment. Furthermore, there exists a need for a more efficient and effective quick freezing system for a refrigeration appliance that can be used in the household environment.
The invention is directed to a refrigeration appliance used to quickly freeze or chill food or beverage items. The appliances can fit under a standard kitchen cabinet in a manner generally analogous to a dishwasher or be provided as a stand alone unit. A large capacity vapor compression refrigeration system is incorporated to develop a flow of circulated cold air that is delivered to an insulated cavity of the appliance. The cavity may be accessed through a drawer, door or the like and can contain accessories such as baskets, shelves, etc. The flow of cold air is preferably discharged from the top and sides, with return air being routed through a bottom space.
In a preferred form of the invention, an additional, small capacity refrigeration system is also incorporated in the appliance to provide cooling, preferably through natural convection, to maintain a desired temperature within the cavity when the rapid cooling is not needed. A thermal storage medium, such as a phase-change material having an associated high latent heat of fusion, may also be provided. Here, the large refrigeration system is used to freeze the phase change material and then the cavity is maintained in a desired temperature range by passing a flow of air developed by an auxiliary fan over the phase change material or through the use of the small capacity refrigeration system. The phase change material can also be used as thermal storage to supplement the cooling capacity for the blast freezing in connection with the large refrigeration system.
In a further aspect of the invention, an impingement air diffuser arrangement is provided within the cavity to direct the air flow used for product freezing or cooling to top and side ports, preferably defined by an array of nozzles. These nozzles can be round or slotted in accordance with the present invention and function to direct an impinging flow of cold air directly onto the food product. The configuration of the diffuser can be altered to define sub-spaces within the cavity for different food packages. In a preferred form of the invention, a vertically adjustable shelf support arrangement is provided within the cavity, with the shelf being made of a finned metal. The shelf cooperates with blocking plates which move up and down with the shelf and function to block air flow through a predetermined number of nozzles arranged below the shelf, such that all of the developed air flow is used for direct impingement on the food product.
Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments thereof when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.